Add values of cells from differenct columns to new column only if cells are not blank

Good day,

I have an excel file and what i want is to sum two different columns to a third one, however there are some important notes:

1. Column A has dates
2. Column B has numbers f.e. 25, 30, 35 etc. , which have to be added to dates of column 1 , so a new date will be created in the new column
3. Colums A and B are not next to each other.
4. Some cells of column A and column B are blank , actually columns are sth like this
A B C
5/2/2014 25
blank blank
8/5/2014 35
10/9/2014 30
blank blank

When a date value occurs in a cell of column A , then always a number will occur in column B
When a cell is blank is column A , then the respective cell of column B will also be blank

What i want is to add values of column A and B to create column C automatically ( each column has 1000 cells ) , however in case of blank cells , i want a blank cell in column C, not something like #####
Apart from this , i want in the future , when i expand column A and B , when values are entered there, i want column C to be created automatically

I hope what i say is easily understood and am kindly waiting for advise

Thank you and regards

Hello and thank you for answers!


what i want in column I is : to add F days to E date
and in column J : to add G days to E date
If cell in column E-F-G is blank , then i want blank cell in columns i and J !

I uploaded an example!

thanks in advance!

The problem is that if i type a simple Sum command and do it for all cells of I and J columns , i get a result like ####### when blank data is in columns E F G !!!

Fotis1991 Thank you-Eyxaristw Poly!! +++++

DOne! Have a nice weekend!

Hello it seems that this is not yet solved!
If I type a date in column E without typing a number in column F then the result in column I is the same as the date in column E ! I dont want column I to be filled unless i type the number in column F ! ( it has to do with my job so sometimes even if i know the date, i do not know immediately the number which i have to input in column F - i might know it after one week )
Tks and sorry for bothering again!